The purpose of this project is to explore the great variety and abundance of the marine environment for molecular models of neurobiology. In particular it was designed to investigate species or phenomena which display an amplification or simplification of human physiologic or pathologic metabolism. Further studies were conducted on the neurotoxic effects of several pesticides in tissue preparations derived from lobster axons and from mammalian brains. Pyrethroid markedly inhibit calcium and dopamine uptake in rat brain nerve ending preparations and in lobster plasma membranes. Comparative studies of brain nucleotide and ecto-enzyme levels in elasmobranch, teleost, reptile, and avian species demonstrated remarkably similar nucleotide profiles but widely differing phosphoesterhydrolase activities.